%0 Journal Article
%T Neuromuscular Activity of Micrurus laticollaris (Squamata: Elapidae) Venom in Vitro
%A Alejandro Carbajal-Saucedo
%A Rafael Stuani Floriano
%A Ch¨¢riston Andr¨¦ Dal Belo
%A Alejandro Olvera-Rodr¨ªguez
%A Alejandro Alag¨®n
%A L¨¦a Rodrigues-Simioni
%J Toxins
%D 2014
%I MDPI AG
%R 10.3390/toxins6010359
%X In this work, we have examined the neuromuscular activity of Micrurus laticollaris (Mexican coral snake) venom (MLV) in vertebrate isolated nerve-muscle preparations. In chick biventer cervicis preparations, the MLV induced an irreversible concentration- and time-dependent (1¨C30 ¦Ìg/mL) neuromuscular blockade, with 50% blockade occurring between 8 and 30 min. Muscle contractures evoked by exogenous acetylcholine were completely abolished by MLV, whereas those of KCl were also significantly altered (86% ¡À 11%, 53% ¡À 11%, 89% ¡À 5% and 89% ¡À 7% for one, three, 10 and 30 ¦Ìg of venom/mL, respectively; n = 4; p < 0.05). In mouse phrenic nerve-diaphragm preparations, MLV (1¨C10 ¦Ìg/mL) promoted a slight increase in the amplitude of twitch-tension (3 ¦Ìg/mL), followed by neuromuscular blockade ( n = 4); the highest concentration caused complete inhibition of the twitches (time for 50% blockade = 26 ¡À 3 min), without exhibiting a previous neuromuscular facilitation. The venom (3 ¦Ìg/mL) induced a biphasic modulation in the frequency of miniature end-plate potentials (MEPPs)/min, causing a significant increase after 15 min, followed by a decrease after 60 min (from 17 ¡À 1.4 (basal) to 28 ¡À 2.5 ( t 15) and 12 ¡À 2 ( t 60)). The membrane resting potential of mouse diaphragm preparations pre-exposed or not to d-tubocurarine (5 ¦Ìg/mL) was also significantly less negative with MLV (10 ¦Ìg/mL). Together, these results indicate that M. laticollaris venom induces neuromuscular blockade by a combination of pre- and post-synaptic activities.
%K snake venom
%K Micrurus laticollaris
%K presynaptic action
%K postsynaptic action
%K neuromuscular preparations
%U http://www.mdpi.com/2072-6651/6/1/359